Download a file from here & see what speed you get
http://www.magnetmix.com/video.shtml
What's your actual speed? You can do a speed test here
http://www.dslreports.com/speedtest?more=1
Have a look through this thread, it's got some good tips for optimising LW's performance
Configuring LW for best performance
Depending on your speed test results (don't get kilobits confused with kilobytes), maybe you should set your speed within LW to another level
LimeWire speeds
Who is your ISP?